package io.xiaojl.xj2ee.common.kit.security.impl;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

import io.xiaojl.xj2ee.common.kit.security.HexUtil;
import io.xiaojl.xj2ee.common.kit.security.IEncrypt;


/**
 * <p>Title: ASCEncrypt</p>  
 *
 * <p>Description: 对称加密算法：ASC加密</p>  
 *
 * @author jilong.xiao  
 * @date 2018年5月23日
 */
public class ASCEncrypt implements IEncrypt {
	//加解密的key
    private String key;

    public ASCEncrypt(String key) {
        this.key = key;
    }

    @Override
    public String encrypt(String string) {
        String base64Encode = null;
        try {
            base64Encode = base64Encode(aesEncryptToBytes(string, key));
        } catch (Exception e) {
        	throw new RuntimeException("ASC进行加密出现异常",e);
        }
        return HexUtil.bytes2Hex(base64Encode.getBytes());

    }

    @Override
    public String decrypt(String string) {
        byte[] bytes = HexUtil.hex2Bytes(string);
        String aesDecrypt = null;
        try {
            String string2 = new String(bytes,"utf-8"); //转回来要注意编码的问题
            aesDecrypt = aesDecrypt(string2, key);
        } catch (Exception e) {
        	throw new RuntimeException("ASC进行解密出现异常",e);
        }
        return aesDecrypt;
    }

    /**
     * 将base 64 code AES解密
     * 
     * @param encryptStr
     *            待解密的base 64 code
     * @param decryptKey
     *            解密密钥
     * @return 解密后的string
     * @throws Exception
     */
    public static String aesDecrypt(String encryptStr, String decryptKey) throws Exception {
        return encryptStr.isEmpty() ? null : aesDecryptByBytes(base64Decode(encryptStr), decryptKey);
    }

    /**
     * AES解密
     * 
     * @param encryptBytes
     *            待解密的byte[]
     * @param decryptKey
     *            解密密钥
     * @return 解密后的String
     * @throws Exception
     */
    public static String aesDecryptByBytes(byte[] encryptBytes, String decryptKey) throws Exception {

        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128, new SecureRandom(decryptKey.getBytes()));

        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));
        byte[] decryptBytes = cipher.doFinal(encryptBytes);

        return new String(decryptBytes);
    }

    /**
     * base 64 decode
     * 
     * @param base64Code
     *            待解码的base 64 code
     * @return 解码后的byte[]
     * @throws Exception
     */
    public static byte[] base64Decode(String base64Code) throws Exception {
        return base64Code.isEmpty() ? null : Base64.decodeBase64(base64Code);
    }

    /**
     * base 64 encode
     * 
     * @param bytes
     *            待编码的byte[]
     * @return 编码后的base 64 code
     */
    public static String base64Encode(byte[] bytes) {
        return Base64.encodeBase64String(bytes);
    }

    /**
     * AES加密
     * 
     * @param content
     *            待加密的内容
     * @param encryptKey
     *            加密密钥
     * @return 加密后的byte[]
     * @throws Exception
     */
    public static byte[] aesEncryptToBytes(String content, String encryptKey) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128, new SecureRandom(encryptKey.getBytes()));

        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));

        return cipher.doFinal(content.getBytes("utf-8"));
    }

}